In a final recommendation statement, the task force affirmed their "A" level recommendation (a high certainty of substantial net benefit), stating that there was "convincing" evidence that screening asymptomatic, nonpregnant adults at high risk of syphilis infection provides "substantial benefit."

High-risk individuals include patients with another sexually transmitted infection, such as HIV, men who have sex with men (MSM), or young, sexually active people, particularly in socially disadvantaged areas. The task force noted clinicians should also consider individuals with a history of incarceration or commercial sex work.

"Accurate screening tests are available to identify syphilis in populations at increased risk [and] effective treatment with antibiotics can prevent progression to late-stage disease, with small associated harms," they wrote in the Journal of the American Medical Association.

Screening recommendations for pregnant patients (also an "A" recommendation) were addressed in a separate statement in 2009.

The recommendation to screen persons living with HIV is an update from the 2004 recommendation statement, as one study suggests that people with HIV are 86 times more likely to acquire syphilis. Among primary and secondary syphilis cases with known HIV status, 51% of cases among MSM were HIV-positive compared with 11% of cases among men who have sex with women, and 6% of cases among women.

This recommendation is timely and certainly an opportunity for primary care providers to address the risk of their patients, and to recommend syphilis screening in order to do early identification and treatment because we know that you can cure syphilis, and reduce sequelae both for the person and any perineal transmission," Ann Kurth, PhD, RN, MPH, a USPSTF member and guidelines co-author, told MedPage Today.

Overall, there were 20,000 cases of syphilis reported in the U.S. in 2014, which was the highest number reported since 1995. Prevalence is the highest among men ages 20 to 29 years, and black individuals among racial/ethnic groups (18.9 cases per 100,000), and higher in metropolitan areas. Overall, 90.8% of cases were men.

They speculated on reasons for the increase, including cuts to public health budgets, change in sexual behaviors among MSM and individuals with HIV (particularly the rise of the Internet for sexual partner identification), as well as the reduced national health focus on sexually transmitted infections other than HIV.

"Health care practitioners need to do a much better job of taking a sexual history and applying recommended screening approaches to the persons for whom they provide care," they wrote. "Misplaced concerns about patient objections to sensitive questions raise the likelihood of failure to identify high-risk patients and result in missed screening opportunities."

High-risk adolescent populations were also included in the USPSTF recommendation, with one survey indicating that 2.5% of boys, ages 15-19 years, and 5.6% of men, ages 20-24 years, reported having sex with another male.

"In an observational study of adolescent health maintenance visits ... the average time of sexuality talk was 36 seconds [and] only 4% of adolescents had prolonged conversations with their physicians," they wrote. "Pediatric clinicians' lack of sexual dialogue, especially around same-sex behavior, will inevitably lead to further missed opportunities to identify behaviors that place young men at risk for syphilis and HIV infection."

Role of Specialists

Traditional screening for syphilis involves a two-part test (nontreponemal test followed by a treponemal test), which has both a high sensitivity and specificity at detecting primary, secondary, and latent syphilis infection. Newer screening methods include a reverse sequence screening algorithm, where the treponemal test is performed first.

"There is limited evidence on this reverse screening algorithm, so we recommend there should be more studies to better understand effect of using it," Kurth said. "But using the standard, widely available, not-very-expensive syphilis blood screening approach is effective and useful."

However, the newer test may have use in the specialist setting. In an editorial in JAMA Neurology, Christina M. Marra, MD, of University of Washington in Seattle, said that the reverse screening algorithm is often used in large laboratories, and that its results may be more useful to neurologists than primary care providers.

"[The] reactivity of serum treponemal tests identifies patients who are at risk for neurosyphilis; conversely, a non-reactive treponemal test result effectively removes neurosyphilis from the differential diagnosis," she wrote. "Patients cannot have neurosyphilis if they have never had syphilis."

Dermatologists may also play a role in screening for various types of syphilis. Kenneth A. Katz, MD, of Kaiser Permanente in San Francisco, wrote in JAMA Dermatology that with an increase in the prevalence of syphilis, dermatologists should be routinely screening their high-risk patients and taking their medical and sexual histories.

"The [USPSTF] recommendation should remind dermatologists that incidence of primary and secondary syphilis has markedly increased," he wrote. "Because those stages of syphilis, by definition, include cutaneous and/or mucous membrane manifestations, dermatologists should include syphilis in differential diagnoses, when appropriate; for a disease often called 'the great imitator.'"

More Research Needed

In addition to more research on various types of screening tests, Kurth said that further studies are needed to evaluate the effectiveness of syphilis screening in high-risk populations, as well as studies that identify effective intervals of screening for people at risk. The CDC currently recommends "at least" annual screening for sexually active MSM and people with HIV, as well as screening in correctional facilities.

In the meantime, Kurth emphasized the role of primary care providers in the screening process, saying they have the power to identify their patients who are at risk.

"It's not really about labels, but about sexual networks people are in. It's always good to know your local epidemiology; rely on your health department for that; and work with the patient population to identify their risks and be able to screen for this highly treatable infection," she noted.

Kurth and co-authors disclosed no relevant relationships with industry.

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